I haven't seen the Holiday Special. I'd never even heard of it until a few years ago, mainly because I wasn't yet alive at the time it was made. With all the negative descriptions I've never been brave or motivated enough to actually go to the trouble of finding it somewhere.
My girlfriend describes it as cheesy, but not as bad as most people say.
Weird Al's music video for 'White and Nerdy' shows him making a shady deal for a copy of the Holiday Special on vhs. lol